ALLHAT is a practice-based, randomized clinical trial of antihypertensive pharmacologic treatment and, in a subset, cholesterol- lowering therapy. Forty thousand high-risk hypertensive patients, age 55 and older, including a high percentage of African-Americans are being recruited. Because diabetes and hypertension occur together frequently and diabetic hypertensives have high rates of cardiovascular disease, a high percentage of diabetic patients were recruited. The primary objective of the double-blind antihypertensive trial is to determine whether the combined incidence of nonfatal myocardial infarction and coronary heart disease death is lower among patients receiving lisinopril (ACE inhibitor), amlodipine (calcium antagonist), or doxazosin (alpha-1-blocker) than in a control group receiving chlorthalidone (diuretic). Secondary endpoints are total cardiovascular mortality, major morbidity, all-cause mortality and health-related quality of life. The primary objective of the lipid trial is to determine whether all-cause mortality is lower in moderately hypercholesterolemic men women patients receiving the cholesterol- lowering drug pravastatin (HMG CoA reductase inhibitor), than in an open "usual care" control group. Secondary endpoints are the combined incidence of nonfatal myocardial infarction and coronary heart disease death, major non-cardiovascular morbidity and mortality, and health- related quality of life. The average duration of follow-up will approximately 6 (4.5 - 7.5) years. Rather than using independently funded clinics, patients are recruited through office-based practices and hypertension clinics which are reimbursed through the Clinical Trials Center on a per-patient basis. This contract is for the Clinical Trials Center. Some of the functions of the Clinical Trials Center include coordinating all data collection, storage of data, analysis activities related to the study, and recruiting and training (along with the NHLBI) appropriate clinical sites and core laboratories require to conduct the study.